Presser bar control for sewing machines



Dec. 19, '1950 R. L'. ABOS EI'AL 2,534,651

PRESSER BAR CONTROL FOR SEWING \MACHINES Filed March 26, 1948 22d RALPH A. A505 22 LAURENCE MSTANF/ao 23 P055 27 5. MYERS STATES PATENT OFFlCE' PRESSER BAR CONTROL FOR SEWING MACHINES Ralph L. Abos, Laurence M. Stanfield, and Robert B. Myers, Los Angeles, Calif., assignors to Revco Products, Whittier, Calif., a corporation of California UNITED Application March 26, 1948, Serial No. 17,265

19 Claims.

This invention relates to means for varying the pressure conventionally applied upon the presser foot members of sewing machines.

Sewing machines are commonly provided with a hollow head in which is mounted a needle bar and a presser foot bar, both of which extend downward below the head, the presser bar being associated with a sprin whose adjustment may be regulated to Vary its compression and thereby vary the pressure which the Dresser foot places upon the fabric being stitched.

It is an object of the present invention to provide a simple and very quickly operable means adapted not only to release the compression upon the presser bar spring so that darning may be readily effected, but it is also an object of the invention to provide such a structure by means of which any intermediate degree of compression desired in the presser bar spring may be obtained and by which any such intermediate compression may be instantly produced.

A further object of the invention is to provide such a compression adjusting device which shall be very simple in construction and inexpensive to manufacture, in addition to providing the mentioned advantage of being quickly adjusted or released.

Other objects of the invention will become apparent to those skilled in this art upon reference The drawing illustrates a conventional sewing machine head H3 having the usual cavity l I which may be enclosed by a removable, conventional cover plate I2. Within the cavity ii there is disposed a conventional needle bar it, whose lower end projects from the head it and carries a needle it, the usual presser bar 55 being disposed behind the needle bar it and also projecting below the head it with its lower end carrying a conventional presser foot it. Upon the presser bar [5 and within the cavity 5 I there is pinned or otherwise secured a collar ll upon which bears the lower end of a conventional, coiled compression spring i8 disposed about the upper portion of the presser bar 55. The upper end of the spring It in the form shown bears against the underside of a washer-like member l9 slidable on the bar l5.

The present improvement comprises a vertically slidable sleeve 26 constituting an adjusting stem having a bore 29a whose lower end telescopically receives the upper end of the presser bar I5 and integrally or frictionally connects with the washer member I!) to control the spring 13. The top of the sleeve 28 is provided with a knob 2i which is adapted to be engaged by the operator to depress the sleeve as as required. The sleeve is mounted in a headed screw 22 having a short threaded shank 23 adapted to be received to the following specification and the accompanyan in corresponding threads in the upper end of the ing drawing wherein certain embodiments of the machine head [8, the head of the screw 22 overinvention are presented by way of exemplificahanging the top of the machine head it and tion, being adapted to be turned down tight there- In the drawing: against to prevent dislodgment. The head of the Fig. 1 is an end elevation of a conventional screw 22 is preferably knurled to facilitate such sewing machine head equipped with a pressure i g, a it s i t r y p v at its p control device of this invention; with a countersink 22a which receives an up- Fig. 2 is a vertical section approximately as wardly acting coil sprin 213 disposed about the taken on the line 2-2 of Fig. 1, the parts being sleeve 20 and bearing upon the underside of a in spring-releasing position; friction lock arm 25 apertured to receive the Fig. 3 is a vertical section similar to that of sleeve 29. One end of the lock arm 25 is free and Fig. 2 showing the parts in the position for reextends outward to present a finger rest 26 for taining the desired compression upon the spring the machine operator. of the presser bar; In the preferred form of the invention illus- Fig. 4 is a view taken from the line 4-4 of trated in Figs. 1 to 5, the lock arm 25 is produced Fig. 3, portions being broken away to facilitate from hardened steel and its inner end is disthe showing; posed in the countersink 22a and retained therein Fig. 5 is a fragmentary vertical section on an by means of an integral short tongue 27 which enlarged scale showing a portion of the structure extends into a slot 28 formed in one side of the of Fig.3; head of the screw 22, the slot 28 leading out- Fig. 6 is a fragmentary vertical section similar ward from the countersink 22a, as best seen in to that of Fig. 5 and illustrating a modification; Fig. 5. A preferably circular aperture 3:) is pro- Fig. 7 is a vertical section showing the parts vided in the lock arm 25 to receive the stem or in Fig. 6 in released relationship; and sleeve 2B. When the lock arm 25 is in locking Fig. 8 is a fragmentary vertical section of a position, it is tilted at an angle as illustrated in further modification.

Figs. 3 and 5 so that it presents to the sleeve a sharp locking shoulder 32 at the lowermost edge of the aperture 30, this shoulder being adapted to bind upon the adjacent side portion of the sleeve 26 to retain the sleeve 26 against upward movement under the biasing influence of the spring 18. The opposite and uppermost edge of the aperture 30 serves as a back wall to hold the opposite side of the sleeve 20 and insure proper retaining engagement of the shoulder 32.

In the form of the invention shown in Figs. 6 and 7, the friction lock arm 25 is produced from spring material and is provided with a spring bend 34 whose normal set is such as to maintain the relationship shown in Fig. 6. The spring bend 34 is an auxiliary to the spring 26. Here, the lower end of the friction lock arm 25 underlies the head of the screw 22 and is apertured to provide an eye 38 through which the short threaded shank 23 is passed. the eye 38 serves as a washer between the head of the screw 22 and the machine head [6. If desired, the spring 24 may be omitted in this form, as indicated in Fig. '7, and the resilience in the spring bend as between the eye 38 and the lock arm 25 relied upon both for the necessary spring action and for such relative movement of the walls of the aperture 38 with respect to the sleeve 29 as is required.

The modification of Fig. 8 is similar to that of Fig. 6,- but here the lower end 35 of the lock arm 25 is bifurcated to provide fingers iil which are received in an exteriorly located annular groove 42 in the head of the screw 22. The coil spring 24 serves to assist the spring bend 36, as

in the case of the form of Fig. 6. However, the friction lock arm 25 and the bend 3-5 of this form may be rigid and without resilience. In this case, play of the fingers 48 in the annular groove 42 will be provided sufiicient to accommodate the necessary movements between looking and releasing positions.

Figs. 5, 6, 7 and 8 are used also to illustrate that the threaded shank 23 of the screw 22 may be very short, it being necessary merely that it be long enough to retain the screw 22 bound in operative position.

In operating the releasing and adjusting mechanism of this invention, the operator presses upon the knob 2| when it is desired to apply pressure to the presser bar spring H5 or to increase the compression. Under such conditions, the sleeve 20 slides readily through the aperture 30 and past the binding shoulder 32. When movement of the knob 2| ceases, the shoulder 32 promptly binds upon the adjacent side portion of the sleeve 29 and looks it against upward motion, thereby maintaining the adjusted compression of the spring It. This is true of all of the forms. When it is desired to release the compression of the spring It, the operator presses the finger rest 26 on the free end of the lock arm 25, the locking shoulder 32 being thus disengaged from the sleeve 2% so that the spring I8 is enabled to function and the sleeve 2% elevated thereby. Under such conditions darning or the like may be readily accomplished. If slight spring pressure is desired for darning, this may be accomplished by depressing the knob 2| slightly. When normal stitching is required, further depression of the knob 2! to attain the desired compression in the spring 58 and the desired pressure upon the fabric under the presser foot it is quickly produced. Thus, it is apparent that any desired compression of the In this instance spring l8 within the range from no compression at all to the maximum compression attainable may be immediately accomplished by the operator with very simple finger movements.

Since other modifications of the invention herein disclosed doubtless will suggest themselves to those skilled in the art to which this improvement pertains, it is intended to cover all variations falling within the scope of the claims.

We claim as our invention:

1. In means for varyin the pressure imposed upon the presser foot of a sewing machine having a head, said foot being carried upon the lower end of a presser bar whose upper end is vertically movable in said head under the pressure of a spring thereon, the combination of: a member having a bore and adapted to be secured in the top of said head of said sewing machine; a stem mounted in said bore to slide vertically the ein, said stem being adapted to telescope with said presser bar and be connected with the upper end of said spring to place the latter under compression; and a spring-actuated lock carried by said bored member and adjustably engaged with said stem to retain the latter at any of a plurality of intermediate positions of vertical adjustment and to place said spring under correspondingly adjustable compression.

2. A combination as in claim 1 wherein said lock comprises a spring-biased lock arm having one end attached to said bored member, the other end of said arm being adapted to be depressed to release said stem.

3. A combination as in claim 2 wherein the top of said stem projects above said member and is provided with means to depress said stem into any desired position of adjustment for engagement by said lock arm.

4. A combination as in claim 1 wherein the top of said stem projects above said member and is provided with means to depress said stem into any position of adjustment for engagement by said lock.

5. A combination as in claim 1 wherein said lock comprises an arm which provides a shoulder locking said stem against movement in one direction.

6. In means for varying the pressure imposed upon the presser foot of a sewing machine having a head, said foot being carried upon the lower end of a presser bar whose upper end is vertically movable in said head under the pressure of a spring thereon, the combination of: a retaining member adapted to be fixed upon said sewing machine head; a stem slidably carried by said member and adapted to place said spring under compression; and spring controlled lock means connecting said stem and said member to hold said stem in any set position of adjustment on said member.

'7. A combination as in claim 6 wherein said lock means comprises a spring-actuated lock arm normally engaging said stem and automatically locking said stem in set position, said arm being manually shirtable to release said stem.

8. A combination as in claim 7 wherein said stem passes through an aperture in said arm providing a shoulder to bind upon said stem.

9. A combination as in claim 7 wherein said lock arm and the top of said stem are disposed above said retaining member whereby to be located in exposed position above said machine head when in operative relationship, said arm and the top of said stem providing means for manual depression.

10. A combination as in claim 5 wherein said lock means includes a lock arm and said retaining member is provided with a spring seat containing a spring operating on said lock arm to move the latter into stem locking position.

11. In means for varying the pressure imposed upon the presser foot of a sewing machine having a head, said foot bein carried upon the lower end of a presser bar whose upper end is vertically movable in said head under the pressure of a spring thereon, the combination of: a retaining member provided with an axial, vertical bore and with a head at its upper end, said member being also provided with a short external thread for binding the headed member on the top of said machine head; a stem slidably mounted in said bore and having means at its top to be engaged for depressing said stem, and being adapted at its lower end for telescopically engaging the upper portion of said presser bar and being operatively engaged with said sprin to vary the compression thereof; and a friction lock arm connected at one end with said retaining member and connected with said stem in engaging relationship to lock said stem by frictional engagement therewith.

12. A combination as in claim 11 wherein said lock arm is provided with an aperture through which said stem passes, edge portions of said aperture serving to bind said stem in adjusted position.

13. A combination as in claim 11 wherein the head of said retaining member is provided with a spring seat containing a spring bearing against said lock arm to move the same to stem-binding 1 position.

14. A combination as in claim 11 wherein said one end of said lock arm is positioned in a retention opening in said retaining member.

15. A combination as in claim 14 wherein said retention opening is located in said head of said retaining member.

16. In means for varying the pressure imposed upon the presser foot of a sewing machine having a head, said foot being carried upon the lower end of a presser bar whose upper end is vertically movable in said head under the pressure of a spring thereon, the combination of: a retainin member adapted to be fixed upon said sewing machine head; a stem slidably carried by said member for slidable adjustment to a plurality of intermediate positions between the extremes of its slidable movement in opposite directions, to place said sprin under correspondingly difierent compressions; and lock means movable between said stem and said retaining member and carried by one thereof for holding said stem set in any of said intermediate positions of adjustment.

17. A combination as in claim 16 wherein said retaining member is provided with means for detachably fixing said member on said sewing machine head.

18. A combination as in claim 16 wherein said lock means includes a movable arm providing shoulder means engaging upon said stem to hold the latter.

19. A combination as in claim 16 wherein said lock means comprises a movable arm carried by said retaining member and presenting a shoulder frictionally engaging the side of said stem to lock the latter against movement in one direction.

RALPH L. ABOS. LAURENCE M. STANFIELD. ROBERT B. MYERS.

REFERENCES CITED Name Date Corson Aug. 20, 1935 Number 

